1 files changed, 112 insertions, 0 deletions
diff --git a/include/nms/web.pm b/include/nms/web.pm
new file mode 100755
index 0000000..7c9339e
--- /dev/null
+++ b/include/nms/web.pm
@@ -0,0 +1,112 @@
+#! /usr/bin/perl
+# vim:ts=8:sw=8
+use strict;
+use warnings;
+use utf8;
+use DBI;
+use Data::Dumper;
+use JSON;
+use nms;
+use Digest::SHA;
+use FreezeThaw;
+use URI::Escape;
+package nms::web;
+
+use base 'Exporter';
+our %get_params;
+our %json;
+our @EXPORT = qw(finalize_output now json $dbh db_safe_quote %get_params get_input %json);
+our $dbh;
+our $now;
+our $when;
+our %cc;
+
+sub get_input {
+	my $in = "";
+	while(<STDIN>) { $in .= $_; }
+	return $in;
+}
+# Print cache-control from %cc
+sub printcc {
+	my $line = "";
+	my $first = "";
+	foreach my $tmp (keys(%cc)) {
+		$line .= $first . $tmp . "=" . $cc{$tmp};
+		$first = ", ";
+	}
+	print 'Cache-Control: ' . $line . "\n";
+}
+
+sub db_safe_quote {
+	my $word = $_[0];
+	my $term = $get_params{$word};
+	if (!defined($term)) {
+		if(defined($_[1])) {
+			$term = $_[1];
+		} else {
+			die "Missing CGI param $word";
+		}
+	}
+	return $dbh->quote($term) || die;
+}
+
+# returns a valid $when statement
+# Also sets cache-control headers if time is overridden
+# This can be called explicitly to override the window of time we evaluate.
+# Normally up to 15 minutes old data will be returned, but for some API
+# endpoints it is better to return no data than old data (e.g.: ping).
+sub setwhen {
+	$now = "now()";
+	my $window = '8m';
+	my $offset = '0s';
+	if (@_ > 0) {
+		$window = $_[0];
+	}
+	if (@_ > 1) {
+		$offset = $_[1];
+	}
+	if (defined($get_params{'now'})) {
+		$now = db_safe_quote('now') . "::timestamp with time zone ";
+		$cc{'max-age'} = "3600";
+	}
+	$now = "(" . $now . " - '" . $offset . "'::interval)";
+	$when = " time > " . $now . " - '".$window."'::interval and time < " . $now . " ";
+}
+
+sub finalize_output {
+	my $query;
+	my $hash = Digest::SHA::sha512_base64(FreezeThaw::freeze(%json));
+	$dbh->commit;
+	$query = $dbh->prepare('select extract(epoch from date_trunc(\'seconds\', ' . $now . ')) as time;');
+	$query->execute();
+
+	$json{'time'} = int($query->fetchrow_hashref()->{'time'});
+	$json{'hash'} = $hash;
+	
+	printcc;
+	
+	print "Etag: $hash\n";
+	print "Access-Control-Allow-Origin: *\n";
+	print "Access-Control-Allow-Methods: HEAD, GET\n";
+	print "Content-Type: text/json; charset=utf-8\n\n";
+	print JSON::XS::encode_json(\%json);
+	print "\n";
+}
+
+sub populate_params {
+	my $querystring = $ENV{'QUERY_STRING'} || "";
+	foreach my $hdr (split("&",$querystring)) {
+		my ($key, $value) = split("=",$hdr,"2");
+		$get_params{$key} = URI::Escape::uri_unescape($value);
+	}
+}
+
+BEGIN {
+	$cc{'stale-while-revalidate'} = "3600";
+	$cc{'max-age'} = "20";
+
+	$dbh = nms::db_connect();
+	populate_params();
+	setwhen();
+}
+1;